Fejes (2005)
and Mjøen (2006) carried out epidemiological
studies on the association of RFR exposure and reproductive
capacity. Fejes correlated semen characteristics with cell
phone use in 371 men attending an infertility clinic, and found
that the men using their cell phones more than 60 minutes a
day had a lower proportion of rapid progressive sperm than
those using their phones for less than 15 minutes a day. Mjøen
linked data on reproductive outcomes derived from the Medical
Birth Registry of Norway with data on paternal occupation derived
from the general population census, and did not find a correlation
between RFR exposure and adverse effects on the men's offspring.
For more on these studies, see "Research
- Epidemiology".

Erogul (2006) studied a semen sample from 27 men. There was
a decrease in the mean percentages of rapid progressive and
slow progressive categories of sperm movement, and an increase
in the percentage of no motility category. This study failed
to mention SAR levels, or whether or not temperature levels
were recorded in the specimens.